Patent ES-353104-A1 (ES)
Title: Automatic viscometer
IPC: G01N11/06
Filed: 1968-04-24
Abstract: The apparatus comprises a known viscometer 3 or several such meters in series or parallel, Fig. 1, a glass bodied electrically heated dissolver 1 provided with a magnetic agitator 11, a thermostatic water tank 4 and pump 5 circulating hot water through the chamber 6 of the meter 3 and through a jacket 7 of the dissolver 1, a solvent reservoir 8 feeding through valves 9, 10, a vacuum generator 12 and valves 13, 14 whereby the solution is sucked from the dissolver 1 into the meter 3, and a discharge tank 15. The dissolver has a specimen charging stopper 22, Fig. 2, a thermometer and casing 36, 23, ducts 2, 24 and two pairs of level detecting electrodes 25, 26, see also Fig. 3 (not shown). The dissolver also comprises a solvent stopper 28 and a solvent dropper 29, and a duct 30 connected to a moisture trap 16. The meter 3, Fig. 4, comprises two tubes 41, level detecting electrodes 42, 43, a non-capillary tube 45 and a tube 46 with a detector 47, the tubes being connected to a vacuum generator through traps and valves. Each detector 42 operates a counter whilst each detector 43 interrupts the counter. Fig. 5 (not shown) illustrates the thermostatic tank which has a heater (53), a cooling coil (52), an air bubbler (54), a thermometer (55). Fig.6 (not shown) illustrates a control system for all the necessary operations including a punched card programming control. In operation the specimen e.g. ethylene polyterephthalate is put into the dissolver 1 through 22 and the appropriate punch card is inserted. A solvent e.g. orthochlorophenol is introduced into the dissolver from the reservoir 8 through the valve 9, and the agitator 11 started. When the solution level reaches the detector 26, valve 9 is closed and the specimen dissolved for 45 minutes. The punch card then operates to stop the heater 35 and the circulating water and the valve 10 is opened to supply solvent to the dripper 29 to allow fine adjustment to be made to the solution. The lowering of the temperature results in a reduction of the volume of the solvent which is then adjusted over a period of 25 minutes through the combined action of valve 10 and detector 25. The punch card then neutralises the level detector 25 and opens valve 13 to admit vacuum to the meter 3 thereby causing solution to rise into 3 to the level of detector 47, which then closes valve 13 and connects the meter to atmosphere. The punch card then ceases programming and the whole operation is repeated by means of a relay (67). The solution then falls by gravity into the dissolver 1 thereby flushing the meter 3. As soon as the detector 43 is uncovered the relay (67) reopens valve 13 and fills 3 again and then gives it a further flushing. Yet a third filling is effected and then the level in the meter is allowed to drop from detector 42 to detector 43, the time taken being automatically counted. The filling and counting cycle is then repeated, again with the solution and yet once more with pure solvent. These times are then ratioed to give a required viscosity figure. After this, programming is continued and the valve 14 opened to discharge the dissolver 1 into tank 15 and then to flush and discharge the dissolver with solvent. Higher solution temperatures of 150 C. may be reached but the thermostatic liquid will not be water and transfer of solution may be effected by pressure instead of vacuum.